Label color gradient

Hello,
I know a similar question has been asked here before several times by other users. But since I've been working with Path Finder every day for years and the task is still unresolved after a very long time I really like to change it now:What do I have to do to switch off the label color gradient? I like to do it myself even in the source code, but couldn't find anything there.

The gradients are simply very annoying for me in the daily use of Path Finder and I have waited long enough for an official solution. It can't be that hard to change.

Thank you very much for telling me what I have to change in which file,
Joachim